1. Field of the Invention
The field of the present invention is printing. More particularly, the field of the present invention is preparing cylinders and sleeves mounted thereon for optimum cylindricity and marking the relationship therebetween for the benefit of matching in future use scenarios.
2. Description of Related Art
It is well-known that printing plates or printing sleeves are mounted on cylinders in a printing operation. The cylinders can include one or more sleeves or other layers thereon. The printing plates are etched or engraved in accordance with a desired image in order to effect the printing operation. It is also known that such etching or engraving of the image on the printing plate can be accomplished by means of a laser.
Typically, a printing press has a set of cylinders, or built-up mandrels, which are used to increase the diameter of the mandrel in the press. Sleeves corresponding to a plate repeat are mounted onto the cylinder. In the case of a printing sleeve, the sleeve itself is imaged as the plate. A typical printing operation for a 10-color press may have three to six sets of cylinders and 100 to 500 sleeves with inner diameters that correspond to the sets of cylinders. The outer diameter corresponds to the print repeat desired.
However, a problem with such known arrangements is that the raised surface of the printing plate, when mounted on the cylinders and sleeves, is not adequately cylindrical. In other words, apart from the etched portions, there are variations in the radii at different positions of the raised surface of the printing plate, measured from the center of the cylinder to the raised surface of the printing plate, thereby providing variations in the cylindricity.
U.S. Pat. No. 7,284,484 to the instant inventor, incorporated herein by reference, describes a method and product to improve the cylindricity of a combination of cylinder and sleeve by laser ablation. This is achieved by a system in which a control device, receiving data on variations in total indicated run-out (TIR) and taper from a detector, instructs a laser in the ablative correction of the sleeve surface to remove the variations through rotational and lengthwise translational movement relative to the sleeve.
While the method is effective in correcting the printing package, a problem exists in the logistics of matching the components of cylinder, sleeve and plate, or printing sleeve, and storing them for reuse. An identification system is needed to restore the unique match of components, thereby to perpetuate the improvement and save costly regeneration of cylindricity.
German patent DE 297 20 298 discloses a printing sleeve for a flexographic printing machine in whose envelope surface an electronic memory module configured as a transponder is introduced for the purpose of identification. Similarly, U.S. Pat. No. 7,308,854 to Rossini discloses an embeddable, activatable, signaling device that stores characterization data. Also, U.S. Pat. No. 6,377,772 to Chowdry discloses an indicia for identification purposes on the sleeve of a cylinder of an electrostatographic machine.
While all of these prior art devices can record, or represent, data, they all require an electronic reader or scanner to interpret the stored information. The recording and reading sophistication of such devices exceeds the simple needs of matching components and introduces unnecessary costs when the storage and cross-referencing of a multiplicity of data is not required. Further, the press operator must carry, or otherwise consult, an electronic display to identify compatible components when a simple visual identification means would suffice. What is needed is a simple marking convention that gives immediate visual recognition to a proper match of components and can be easily and simply applied without embedding electronically-readable assets.